Furnace



Feb. 12, 1935. F.M.1LER 1,990,827

FURNACE Filed Jul5r V26, 1930 3 Sheets-Sheet 1 AF121. 12, 1935. F. M. ER 1,990,827

FURNACE Filed July 26, 195o s sheets-sheet s ,JEL vena I* Patented Feb. l2, 1935 UNITED STATES PATENT orifice 1,990,827 FURNACE Franklin M. ller, Cleveland, Ohio Application July 26, 1930, Serial No. 470,918

2 Claims. (Cl. 126-108) This invention relates to furnaces and more particularly to methods and furnaces for employing the heat of combustion of fuel to heat air for a hot air system, employed for heating,

drying or the like.

ln hot air heating furnaces heretofore employed, the air has been heated in a jacket about a combustion chamber, and the gases of combustion have been passed directly to a chimney. The heat of these gases of combustion has been largely wasted, going merely to heat the chimney and supply the draft for the furnace. It is therefore an object of'the present invention to utilize this ordinarily Wasted heat, and transfer the same to the air being heated for the system. f

An attendant object is to provide an artificial draft in lieu of the draft afforded by the waste heat of the gases of combustion.

Another object of the invention is to provide a heating apparatus which may be used for ventilation purposes in seasons when artificial heat is not required.

it is a further object of the invention to simplify and improve the construction and operation of apparatus of this character, and particularly toimprove the efficiency of the same.

Other objects and features of novelty willbe apparent as the following description proceeds, reference being had to thev accompanying drawings, in which Y l Figure 1 is a plan of a furnace according to the preferred embodiment of the present invention, parts being broken away to show the internal construction.

Fig. 2 is an elevation of the furnace shown in Fig. 1, also broken away to show the internal details.

Fig. 3 is a longitudinal section through a modified type of furnace embodying Vprinciples of the present invention, taken-along the line 3-3 of Fig. 4.

Fig. 4 is a horizontal section of Fig. 3.

Fig. 5 is a vertical section taken along the line 5 5 of Fig. 4, and

Fig. 6 is a vertical sectio-n taken along the line 6 6 of Fig. 4.

Referring more particularly to the drawings, the furnace shown in Figs. 1 and 2 comprises a nre pot l0, constructed of fire brick or other refractory material adapted to attain a very high temperature for heating 'the air solely by radiation. The fire pot 10 is provided with a grate 11 supporting a fuel bed 12 above an ash pit 13 provided with an ash door 14. Sheet metal walls 15 extending above the fire pot 10 enclose therewith a combustion chamber 16 which is provided with a charging door 17 for replenishing the fuel bed 12. The construction described above is enclosed within a sheet metal 5 jacket 18 having a top Wall 19 which may be gypsum board or the like. Smoke pipes 20 are fitted in apertures in the walls 15 and conduct the products of combustion to a sheet metal smoke dome 21. V

The smoke dome 21 is supported upon a heatY interchange chamber, indicated generally at 22, constructed of sheet metal and comprising a substantially cylindrical wallk 23, a top plate 24, and provided with a pair of substantially parallel spiral partitions 25 and 26. A central pipe 27 extends downwardly from the smoke dome 21 and is connected to a smoke passage or flue 28 defined by the partitions 25 and 26. These partitions are so arranged that in addi- 20 tion to providing the smoke flue 28 therebetween, adjacent convolutions of the same also define an air passage 29, so that each of the partitions has on one side a smoke passage and on the other side an air passage, the two pas- Sages forming spiral coils in indirect heat interchange relation by conduction through the partition therebetween.

.A portion of the outer wall 23 of the heat interchange casing is constituted by a plate 30 upon which is mounted a double blower comprising fans 31 and 32, mounted on a common. shaft 33 driven by a motor 34. VThe housings for both fans are carried by the plate 30, so that the same may be installed as a unit. In 35 other words, the blower may be built upon the Y plate 30 by the manufacturer thereof so that the installation will present no problems to the sheet metal workers installing the main portions of the furnace. Y 40 The air to be heated is drawn by the blower fan 31 through the cold air inlet 35 and is forced along the spiral passage 29. The Ysmoke from the flue 28.is drawn by the fan 32 and ejected through the smoke outlet 36. Thus the air to be heated passes counterflow to the gases of combustion.

It should be noted that the fire pot 10 issurrounded by a radiation chamber 37 formed by the wan 1s and a. portion of the wan 2s. Air 50 from the passage 29 may pass into the chamber V37 through apertures 38 in the lower part of the wallI 23. The chamber 37 communicateswith the conduit 39 below the top plate 19 and surrounding the pipe 20. This conduit is also in 5 of the air. 40

communication with a jacket 40 surrounding the smoke dome 2l. Thus the air to be heated may comprise a stream passing along the spiral conduit 29,.y and another stream passing directly into the radiation chamber 37. The air in the chamber 37 is heated by radiation and the air passing therefrom up along the pipes 20 reaches the jacket 40, where it is commingled with theA and in VView of the temperature gradient it follows that the air heated by convection does not attain ashigh a temperature as the air heated by radiation. YThe commingling ofthe streams of air serves to combinerthe advantages of heating by radiation With those of heatingby ,convection. The streams of air after being com- Kmingled inthe jacket 40 may be piped out through outlets 41 to various rooms of `a building or the like.

The flow of air through the passage 29 may be controlled by a damper 42 fitted in an aperture 43 inthe wall 23, which when opened, will reduce the pressure generatedgby the fan 31, and hence decrease the flow. In mild weather, when very little heat V,is required, the blower may be cut off, and smoke may be piped from the dome 21 directly to the chimney through' the pipe 44, the opening 42 permitting natural circulation In warm weather the fire may be discontinued, and the blower operated to circulate cool air through the outlets 40, thus serv ing for cooling and Ventilating.

, The construction shown in Figs. 3, 4,` 5 and 6l embodies the principles of the furnace described above, but the same is in a rectangular form, which is more desirable lfor the sake of appearance, and employs a larger amount of tile or masonry constructionV inlieu of sheet metal, although the same is not 'entirelyeliminated. In this arrangement the furnace comprises a rectangular tile orV masonry shell 49. The construction of the :tire pot 10 and'related elements4 of the combustion chamber of thisv -furnace are similar to those described in connectionwith the preferred embodiment and will therefore be given the same reference characters v and not again described indetail, the modifica- Ved to form similar return bends 57 for the spaces 58 between the fiues 55 so that the spaces 58 and bends 57 form a similarsinuous coil intertted with Vthe first coil, but at right angles thereto.

Smoke pipes 59 extend from the combustion chamber 16 and connect the same with the top The tiles of thev return bend 56 of the wall 52, and thus pass the gases of combustion through the coil formed by the pipes 55 and return bends 56, thus giving the gases a back and forth travel longitudinally of the furnace.

The blower casing 60 is fitted into a preformed matrix in the solid masonry construction below and to one side of the fire pot 10. A duct 61 in the partition 51 passes the gases of combustion `from the lowest pipe 55 to the fan 32, by which they arel forced out of the exhaust pipe 62.

'VI-rhe air to be heated is forced by the fan 31 through a duct 63 into the coil formed by the spaces 58 and bends .57, thus giving the air a back and'rforth travel transversely of the furnace. The air is thus maintained inindirect heat interchange relation by conduction throughV the walls of the pipes 55 with the gases of combustion therein. The air is generally ascending, while the gases areV descending, thus causing a general counterflowrelation. As the air is passing transversely while the gases 4are passing longitudinally of the furnace, there is a cross Vtravel relation.

A part of the air Ymay be bled from Ythe con-- vection coil through ducts 64 to the radiation chamber 65. The stream of air from thespaces 58 whichv has been heated by convection, is com-Y mingled withY the stream of air from the chamber 65 which has been heated by radiation, as these streams enter the chamber 66 surrounding the smoke pipes 59. The'mixture passes therefrom through the fittings 67 for supply to desiredoutlets` in the building or the like to be heated.

In this arrangement, When the blower is Ycut off for mild heating, the smoke may pass out nection withtheform shown in Figures 1 and 2. Y

In both forms of the invention I contemplate making the plates of the heat interchanger corrugated, either annularly ortransversely, so as to permit expansion and contraction thereof without disturbingv the other parts, to avoid quaking, increase thesurface and toY strengthen the same against collapse.

YWhile thesev embodiments of the invention have beenv illustrated and describedV in such detail as to enable any one skilled in the art to practice the invention, nevertheless it is to be understood that the inventionA is not to be limit ed to any of the details disclosed otherthan as necessitated by the development of the prior art, but instead it will be understood that the invention embraces such embodiments of the broadiidea as fall within the scope of the subjoined*l claims, it being obvious that various changes may be made without departing from the spirit of the invention. y

Having thusv described my invention what I claim is: Y

1. A furnace for a hot air system comprising acombustion chamber constructed of refractory material, means for admitting fuel and kair to saidrcrombustion chamber, a radiation chamber constructed of refractory material substantially surrounding said combustion chamber, a convection chamber constructed of refractory material, metal partitions in'said convection chamber supported by said refractory material ldividing said' convection chamber into 'interfitting elongated air `heating and gas conductingvflues in indirect heat interchange relation through said partitions, means for passing gases of combustion from said combustion chamber to said gas conducting flue, means for passing heated air from said air heating flue to said radiation chamber, means for forcing a stream of air to be heated along said air heating flue and a second stream of air through said radiation chamber into said system, and means for withdrawing cooled gases of combustion from said gas conducting flue.

2. A hot air furnace comprising a combustion chamber, a refractory casing surrounding said combustion chamber, a refractory partition in said casing, spaced flues supported by said casing and said partition, alternate adjacent ends of said nues being connected by a passage in the refractory material of said casing and said partition forming a continuous smoke passage, means for passing gases of combustion from said combustion chamber to said smoke passage, alternate adjacent sides of the spaces between said flues being connected by passages in the refractory material of said casing to form a con-v tinuous air passage, and means for circulating air to be heated through said air passage.

FRANKLIN M. ILER. 

